For example, the voice actors for the protagonists of the anime film Uchiage Hanabi, Shita kara Miru ka? Yoko kara Miru ka? are Suda Masaki and Hirose Suzu, who are best known for their acting careers. Compared to other professional seiyuus in the industry, both of them have much less experience in voice acting.
On the other hand, famous seiyuus (i.e. Miyano Mamoru, Hanazawa Kana, and Kaji Yuki) were given a supporting role in the film.
Regardless of their performance in the film (cause it's not out yet), I was curious if there are any reasons these anime films tend to use film actors? Since there are a huge pool of seiyuu working in the industry.
Furthermore, Kamiki Ryunosuke and Kamishiraishi Mone got a leading voice acting role in Kimi no Na wa. They both did a great job and even received an award for it. However, it seems to me that they only do voice acting for anime films (especially Kamiki Ryunosuke).
Is there a particular reason for this? Or is it just a marketing strategy to use these big actors' names in the film?